Singletary vetoed the deal, per the report.
The 49ers had Alex Smith, a former first-round pick. To that point, the quarterback had been a disappointment, but Singletary believed in him.
"But Singletary liked Smith, saw his potential, and knew he had worked with four coordinators in his first four years," wrote Pompei. "He wanted to give him a chance, and he told him he would."
Singletary didn't want to transition from Smith to Roethlisberger. At the time, he felt Smith was a better representative of what he was trying to build in San Francisco. Looking back, though, Singletary probably would have chosen differently.
"I had been telling the team I wanted a team of character," Singletary told Pompei. "I felt I had to be true to that. But if I could do it again, I'd do it differently."